Charges on deliveries from UK

Hi everyone.
Postman arrived with a package from the UK this morning marked as a ‘gift’, and valued at £40. It’s a pair of glasses that I left at my parent’s house.
The UK post office filled in the form for my mum - unfortunately when the post office worker asked the value of the contents of the package my mum plucked a figure out of the sky and said £40.
When our postman arrived this morning told me I had to pay 20 euros before he’d let me have the package.
Looking back on the old threads, am I right in thinking that I’ve been charged a duty/handling fee because the value of the ‘gift’ comes to over 45 euros (works out at 46.80 euros with today’s exchange rate :face_with_symbols_over_mouth:)!

Also, our very nice postman gave me an ‘avis de passage’ and took the glasses away because he told me that if I flash the QR code on the avis I can pay a lower duty/handling fee (if done before midnight tonight). He’ll then re-deliver the package next week.
Tried to do what he said and flashed the QR code, but I just get a message saying they will be delivering my package - no option to pay. Any advice on how to pay this lower charge via the QR code?
Thanks

It may be that you’re too late to pay by the QR code. I have a delivery on the way, but it’s commercial and they have my email, so I received an email offering the reduced payment.

Perhaps ask at your PO or even ask the postman?